Apparatus method and valve for electrodepositing a coating on interior surfaces of container bodies

ABSTRACT

An electrocoating system comprises an apparatus, method and valve for electrodepositing a coating on interior electricallyconductive surface areas of container bodies. Container bodies having an open end are timely fed onto circumferentially aligned rows of valves on the exterior of a rotating cylindrical drum containing an electrolytic fluid. Continuous anodic cables extend around the drum, exert axial pressure on the bottoms of the containers, render them anodic, sealingly engage their rims on the valves and thereby open the valves to gravity-feed the fluid into the bodies. With fluid therein, current passed through cathodic electrodes projecting from the valve exteriors into the bodies, electrodeposits a coating on the electrically-conductive surface areas of the container bodies. During continued drum rotation, fluid gravitydrains from the coated bodies back into the drum, and the empty, coated bodies are discharged from the system. The fluid valve has a fixed exterior and a moveable interior housing. A valve member connected to the exterior housing has an insulated conductive core to which a spring electrode is connected thereto exterior of the valve member. The interior housing is axially moveable against a spring bias to open a passageway in the valve. All parts of the valve are nonconductive in relation to the fluid.

United States Patent [191 Kossmann Nov. 19, 1974 APPARATUS METHOD ANDVALVE FOR I Inventor:

Assignee:

Filed:

Appl.

Hans Kossmann, Barrington, 111.

American Can Company,

Greenwich, Conn.

July 2, 1973 Related US. Application Data Division of Ser. No. 285,643,Sept. 1, 1972.

US. Cl 204/300, 204/181, 204/275 Int. Cl. C23b 13/00, C23b 5/68 Field ofSearch 204/300, 299, 275, 181,

References Cited UNITED STATES PATENTS Primary Examiner-John H. MackAssistant Examiner-A. C. Prescott Attorney, Agent, or Firm-Robert P.Auber; Paul R. Audet; George P. Ziehmer 5 7] ABSTRACT An electrocoatingsystem comprises an apparatus, method and valve for electrodepositing acoating on interior electrically-conductive surface areas of containerbodies.

Container bodies having an open end are timely fed 7 ontocircumferentially aligned rows of valves on the exterior of a rotatingcylindrical drum containing an electrolytic fluid. Continuous anodiccables extend around the drum, exert axial pressure on the bottoms ofthe containers, render them anodic, sealingly engage their rims on thevalves and thereby open the valves to gravity-feed the fluid into thebodies. With fluid therein, current passed through cathodic electrodesprojecting from the valve exteriors into the bodies, electrodeposits acoating on the electrically-conductive surface areas of the containerbodies. During continued drum rotation, fluid gravity-drains from thecoated bodies back into the drum, and the empty, coated bodies aredischarged from the system.

8 Claims, 10 Drawing Figures is 4 IIII' Q! APPARATUS METHOD AND VALVEFOR ELECTRODEPOSITING A COATING ON INTERIOR SURFACES OF CONTAINER BODIESThis is a divisional of application Ser. No. 285,643, filed Sept. 1,1972.

BACKGROUND OF THE INVENTION This invention relates to the field ofelectrocoating metal substrates. More particularly, the inventionrelates to an electrocoating system including apparatus, method andvalve for electrodepositing a coating on interiorelectrically-conductive surface areas of metal container bodies.

Basically, electrocoating is the electrodeposition of organic resinouscoating materials on electricallyconductive surface areas, frompolyelectrolytic electrocoating material mediums which can be anodic orcathodic aqueous or nonaqueous base bath solutions, suspensions ordispersions. The electrocoating mediums ultimately contain coating ionsor polyelectrolytic particles, which, in the case of anodic mediums,carry a negative charge in the bath and when a voltage is applied andcurrent is induced to flow through the medium, migrate to and dischargeonto any positively charged surface of a metal substrate, i.e., theanode, which may in contact with the medium. Conversely, the

' polyelectrolytic particles, in the case of cathodic mediums, carry apositive charge in the medium, and, upon application of a voltage,migrate to and discharge onto any negatively charged surface of a metalsubstrate, i.e. the cathode, which may be in contact with the medium.

A layer of particulate coating material is electrodeposited adjacent theelectrically charged metal substrate as the direct current flows betweenit and an oppositely electrically charged electrode such as a wire orrod, immersed in the coating bath. The process is driven by anelectrical potential which can be in the range of from 1 up to 500volts, but more typically is from about 50 to 500 volts. Theelectrodeposition of the coating material takes place only atelectricallyconductive surface areas of the metal object because only atsuch areas is there an electrical circuit and the electrical actionwhich allows the flow of direct current needed to cause thepolyelectrolytic particles to be electrodeposited adjacent theelectrically-conductive surface.

The thickness of the layer of particulate material electrodeposited isautomatically regulated by the characteristically low electricalconductivity of the particular mediums used. Once a certain layerthickness of coating material has attached to the electricallyconductivesurface area of the metal substrate, the electrodeposited coatingmaterial, in having a low elec' trical conductivity characteristic,increasingly tends to insulate the surface area from the coating bath inwhich it is immersed, transforming it into a non-conductive surface,whereby direct current flow therein greatly diminishes and eventuallyceases, with the resulting inhibition of further electrodesposition ofcoating material.

One particular field where it has been found desirable to coat metalsubstrates is in the manufacturing of metal containers or cans, where itis necessary that all the exposed, uncoated surface areas on the metalcan be coated to protect the metal from corrosion.

At present, there is no conventional, commercial apparatus or method ofquickly and efficiently electrocoating the interior surfaces of metalcan bodies such as used in the packaging of beer or carbonatedbeverages. Presently, a typical method of perfecting coverage of thecoating on the interior of such surfaces to protect them fromenvironmental product attack, is to use a double coat system whichinvolves initially applying a base coat by a roller onto the metal stockwhile it is in the flat, and, after fabricating the can from the coatedstock, spraying a top coat on the interior of the fabricated can orcomponent to seal any scratches, breaks or discontinuities or otherelectrically porous or conductive areas formed in the base coat during.the fabrication operation. The top coat usually is an overall coat sincethe location of the discontinuities cannot precisely and reliably beascertained.

While this two coat system has in general been satisfactory, it doeshave a number of disadvantages, especially in relation to the overalltop spray coat. One is that it is relatively difficult to apply anoverall top coat at high speeds because of problems usually associatedwith spraying machines. These include contamination of machine parts dueto overspray, the need for frequent cleanups and adjustments of sprayheads, and the need to bake the finished ends to drive off solvents thathave to be used to obtain the viscosity requisite for spraying top coatmaterials. The presence of solvents in the spray coat is problematicalbecause they are dangerous to inhale and handle. They also pollute andrequire expensive exhaust and other pollution-preventing handlingsystems.

High speed commercial spray coating machines require deposition ofrepair coats in 2 seconds or less. At such speeds, spraying often doesnot obtain satisfactory seals of imperfections because the predeterminedamount of material sprayed throughout the interior of the can body oftendoes not provide enough material adjacent a particularly largediscontinuity to adequately seal it.

Spraying an overall coat often does not provide uniform coatings sincetoo little solvent results in too little coverage in some areas andlumps or accumulations in other areas, and too much solvent causesdripping, sags and runs.

Spraying is wasteful because coating material is applied to the entireinterior surface area rather than limitedly as and where it is needed.

Lastly, spraying an overall top coat causes webbing and frilling aboutthe pouring openings of easy-open can ends, due to the top coatcompletely covering the base coat and often adhering more strongly tothe base coat than the base coat to the can ends, when the scoredefinedeasy-open tear out portions are removed therefrom.

The electrocoating system of this invention solves all of theaforementioned disadvantages and problemsand others as well. It is fastenough for commercial high speed operation. It has been used for exampleto repair coat in 2 seconds or less at rates of 600 cans per minute.There is virtually no contamination of machine parts due to overuse, andthere is less need for cleanups and adjustments.

The system is selective, self-limiting and nonwasteful: lt depositsuniform coatings of sufficient quantity to attain satisfactory singleand repair coats which do not web and frill.

The system is advantageous because aqueous electrocoating solutions canbe employed therewith. These are not dangerous to handle and preventpollution of the atmosphere by not requiring solvents. Aqueous materialsdo not require expensive solvent exhaust and handling systems. An addedadvantage is that the system of this invention can be used in place offour conventional body spray machines.

This system is especially advantageous because it can be used to apply asingle full coat which satisfactorily coats the entire interior surfaceareas of the container bodies, or it can be used to repair or spot coatonly imperfcctions in a previously applied base coat.

Numerous other advantages of the electrocoating system of this inventionincluding apparatus, method and valve will be apparent as it is betterunderstood from the description which follows, which, taken inconjunction with the drawings, discloses preferred embodiments thereof.

SUMMARY OF THE INVENTION portions of the valve means in contact with thefluid being non-conductive in relation thereto; an electrode, preferablya helical spring, connected to and projecting radially from the exteriorof the valve means; the valve means including: means for carryingelectric current therethrough to the electrode, a housing having fixedand moveable portions, the moveable portion having a mouth therein, avalve member fixedly connected to the fixed housing portion, andpreferably'having a metal core running therethrough, the core beingincluded within the current carrying means, biasing means mountedbetween the fixed and moveable housing portions, and a resilient sealingring located on the mouth of the moveable housing portion and moveablybiased by the biasing means into sealing engagement with the valvemember; means partly mounted on the drum for creating a potentialdifference between the electrode and the interior conductive surfaceareasof the container bodies, the aforementioned portionrof thepotential creating means, preferably being a commutator assembly meansmounted interiorly of the drum and including intermediate circuitryconnecting it to the current carrying means; and, means for feeding thecontainer bodies onto the valve means so that the bodies are registeredthereon, the electrode projects into the interior of the bodies and therims of the bodies sealingly engage the sealing ring with pressuresufficient to break the sealing engagement between the valve member andthe sealing ring to create a passageway therebetween which allows thefluid to pass through the valve means and into the container bodiesduring a portion of the reservoir rotation, so that a potential createdelectrodeposits a coating on interior electrically-conductive surfaceareas of the container bodies.

The feeding means can include means, preferably cradles, mountedradially on the cylindrical wall adjacent each valve means for receivingthe container bodies from a source and placing the bodies in registeronto the sealing rings so that the electrode projects into the interiorof the bodies. The feeding means can also include means for holding thecan bodies in registered sealing engagement on the sealing ring and forproviding pressure sufficient to create a passageway between the valvemember and the sealing ring which allows the fluid to pass through thevalve means and into the container bodies during a portion of the drumrotation so that the potential created during that portion of rotationelectrodeposits a coating on interior electricallyconductive surfaceareas of the container bodies.

The apparatus can also include means connected to the interior of thedrum for, preferably pressuredly, charging, leveling and draining thefluid to, in and from the drum, and it can include means for removingthe container bodies from the valve means and from the drum. Theremoving means can include a knife for separating the rims of thecontainer bodies from the sealing ring of the valve means.

The .axis of the drum can be tilted and its noncylindrical wallsarcuate, so that liquid on the drum walls does not accumulate thereonbut drains toward the bottom portion of the drum.

The method of the invention comprises rotating, preferably continuously,a reservoir or drum containing an electrolytic fluid and having valvemeans mounted in the exterior walls thereof, the valve means in turnhaving an electrode projecting therefrom; feeding, preferablysimultaneously, the container bodies onto the valve means so that thebodies are registered on the valve means and the electrode projects intothe interior of the container bodies, providing axial pressure againstthe container bodies, preferably against their exteriormost ends,sufficient to sealingly engage the rims of the can bodies against aportion of the valve means and to open the valve means; passing thefluid from the rotating drum through the open valve means and into thesealingly engaged bodies; creating a potential difference between theelectrode and the interior surfaces of the bodies when they contain thefluid; and thereby electrodepositing a coating on the interiorelectrically-conductive surface areas of the bodies.

The pressure providing step can be maintained throughout a major portionof the drum rotation and the fluid passing step, preferably, is effectedby gravity. The method can also include the steps of insulating themeans for creating the potential and the means for carrying the electriccurrent through the valve means to the electrode, and charging the fluidto the drum and removing the coated container bodies from the valvemeans and from the reservoir.

The fluid valve of this invention for electrodepositing systems whereinan electrolytic fluid and electric current insulatedly pass through thevalve, comprises: a fixed exterior housing mountable on a wall of areservoir containing the fluid, the exterior housing having a back wallwith apertures therein communicating with the interior of the reservoinamoveable interior housing, interior of and slidingly engaged with theexterior housing, the interior wall of the interior housing defining acentral valve chamber and having a mouth opposite the back wall; aresilient .sealing ring mounted in the mouth; a valve member fixedlyconnected at one of its ends to the back wall, extending axially intothe chamber and having legs fixed to and extending transverse to itsaxis, the axial portion of the valve member having a conductive coreconnectable to circuitry; an electrode, preferably a helical spring,connected to and projecting, preferably radially, from the exterior ofthe valve member; means for sealing and preventing fluid from passingbetween the housing; and biasing means, preferably a helical springextending around and being abuttingly biased against a support wall ofthe interior housing, for flexibly biasing the sealing ring and theinterior housing into sealing engagement with the valve member legs toseal the fluid valve chamber, the biasing means being inwardlycompressible towards the back wall by an axial force so that when theforce is sufficient to compress the sealing ring and biasing means, apassageway is created between the valve member legs and the sealing ringwhich allows fluid to flow from the reservoir to the exterior of thevalve chamber.

Preferably, all parts of the valve exposable to the fluid excluding theelectrode are non-conductive in relation to the fluid. The biasing meanscan also include a rigid backing ring adjacent the back wall of theexterior housing for backing the spring, and a rigid lock washer mountedbetween the backing ring and the spring, for backing the spring andacting as a stop against outward movement of the interior housing. Thefluid sealing and preventing means can include an annular, flexible,resilient interior sleeve partly within the chamber and sealinglyfastened to the interior of the interior housing and the exterior of theexterior housing to prevent fluid from passing therebetween, and an annular, flexible, resilient exterior sleeve sealingly fastened to and forsealing the exteriors of the interior and exterior housings, exterior ofthe reservoir wall. The fluid sealing and preventing means can furtherinclude an annular, elastomeric O-ring between the back wall and aninterior sleeve portion that is adjacent the backing ring.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation showingthe electrocoating apparatus of this invention.

FIG. 2 is a plan view taken substantially along line 22 of FIG. 1.

FIG. 3 is an enlarged vertical section taken substantially along line 33of FIG. 1 showing a portion of the drum and the valves mounted thereon.

FIG. 4 is an enlarged perspective view of one of the cradles mounted on,but shown broken away from, the reservoir of FIG. 3.

FIG. 5 is an enlarged vertical section through a portion of theelectrocoating reservoir and through a fluid valve mounted thereinbefore a can body is placed on the valve.

FIG. 6 is an enlarged vertical section similar to that of FIG. 5,showing the fluid valve in an open position and liquid passing from thereservoir into a can body placed on the valve and shown partly brokenaway.

FIG. 7 is a plan view taken substantially along line 7-7 of FIG. 6showing apertures in the valve housing wall.

FIG. 8 is a front view of the commutator assembly of FIG. 3 with partsbroken away showing some of its mechanisms and electrical circuitry.

FIG. 9 is a top view taken substantially along line 9-9 of FIG. 8.

FIG. 10 is a vertical section taken substantially along line l0l0 ofFIG. 8.

DETAILED DESCRIPTION OF THE INVENTION In a preferred, exemplaryembodiment of this invention, FIG. 1 shows an electrocoating orelectrodepositing system generally designated 10 comprising a rotatablereservoir or drum 12 rotatably mounted on a main frame 15. The reservoir(hereinafter drum) is driven by means for rotating the drum whichinclude drive means such as motor 16, whose flange 17 is mounted to aframe (not shown). Motor 16 drives pinion gear 18 mounted on shaft 19which drives main ring gear 20 fixed to an interior wall (not shown) ofdrum 12. Ring gear 20 in turn drives feeding means generally designated22 for feeding container or can bodies 44 onto drum 12, and discharge ortake-off means generally designated 23 (hereafter discharge means) fordischarging coated container bodies 44 from drum l2. Coated in thiscontext means full or repair coated by an electrolytic fluid 84 in drum12 according to this invention. Ring gear 20 drives both feeding means22 and discharge means 23 by driving pinion gear 24 rotatably mounted onshaft 25, mounted on flange 25 and fixed to pulley 26. Pulley 26 drivesbelt 27 which in turn drives pulley 28 rotatably mounted on shaft 29,mounted on flange 29, and fixed to pulley 30. Pulley 30 drives belt 31shown connected to pulley 32 which in turn drives belt 34 connected topulley 36. Box 37 represents mechanism (not shown) sufficient totransfer the rotary motion of pulley 36 into timed simultaneous rotationof feeding means 22 including shafts 38 (shown) and 39 (FIG. 2)respectively fixedly connected to worm feed screws 40 (shown) and 42respectively having grooves 41 (shown) and 43 for timedly feeding canbodies 44 to means included within the feeding means such as cradlesgenerally designated 46 for placing the container bodies in register onvalve means 50 and on electrodes 48 connected to and projecting fromvalve means 50 mounted in the exterior of, preferably cylindrical, wall52 of drum 12.

Pulley 32, driven by belt 31 and also fixed to pulley 54 on a shaft (notnumbered), drives belt 56 which in turn drives pulley 57 fixed to a setof miter gears 58 (not shown) and 59 connected to other suitablemechanisms in box 60. The miter gears are connected to other mechanisms(not shown) sufficient to rotate a series of vertical shafts 62 (FIG. 2)fixedly connected to drive pulleys 63, on which are mounted continuousdischarge or take-off belts 64, also mounted on series of idler pulleys65 on shafts 66 mounted to a broken away portion of frame 67. Pairs ofdischarge belts 64 engage the sides of coated can bodies 44', lift themfrom cradles generally designated 46 and transfer them to removal chutescomprised of side discharge guard rails 68 and upper and lower dischargeguide rails 70. Coated can bodies 44' can be further moved along theguide rails away from electrocoating system 10 by any suitable meanssuch as a series of turrets, guide rails and moving belts (not shown)which, for example, could reverse their direction and move them to otherstations for further processing.

As motor 16 drives ring gear 20 to continuously rotate drum 12 in aclockwise direction, and as it also simultaneously and timedly drivesworm feed screws 40 and 42 to place uncoated can bodies 44 in registeron valves 50, the can bodies are held in register by holding means suchas continuous cables 72 (one shown) driven by the rotation ofdrum 12.Cable 72 passes over roller 74 mounted on shaft 78 and insulating sleeve79, and over roller 76 mounted on shaft 80, each being respectivelyrotatably mounted on broken away arms 81 and 82. Brush 71 on arm 73(broken away) connected by wire 75 to a negative D.C. source (notshown), engages and thereby imparts an anodic, negative charge to cable72. Roller 76 brings cable 72 into engagement with cradles 46 and thebottom ends of uncoated container bodies 44. This imparts the negativecharge to bodies 44, renders them anodic and pressuredly holds thebodies against valves 50 as drum 12 rotates for a major portion of its360 of rotation. Cable 72 supplies sufficient axial pressure againstbodies 44 that their rims of their open ends abutting valve 50 sealinglyengage sealing ring 156 (described later) of valve 50, and the rimpressure opens the valves so that, as substantially hollow drum 12rotates in a clockwise direction, electrolytic fluid 84 containedtherein passes, preferably by gravity, through valve 50 and fills cans44 on the lower portion of drum 12 without leakage of electrolytic fluid84 from the system. As further explained later, when can bodies 44 arefilled with fluid 84, a potential is created between electrodes 48 andinterior electrically-conductive surface areas of can bodies 44 so thata coating is electrodeposited on the surfaces. As drum 12 continues torotate the upper portion of cable 72 separates from coated can bodies 44and allows them to be removed from valves 50 and cradles 46 fordischarge from the system.

FIG. 2 is an enlarged top view taken along lines 2-2 of FIG. 1 and showsa portion of discharge means 23 of the apparatus of this invention. Moreparticularly, FIG. 2 shows an upper portion of cylindrical drum wall 52underlying a series of aligned shafts 62 and dummy rollers 63, and 66and 65, the former of which are drivingly rotated in such directionsthat, as shown, the inner portions of upper and lower pairs of dischargebelts 64 cooperate to engage the sides of coated can bodies 44' andthereby participate in their removal from sealing rings 156 andelectrodes 48 of valves means 50, and from cradles 46. Belts 64 alsogradually move the cans along a horizontal plane. The rotation of druml2 cooperates in the removal of electrodes 48 and cradles 46 from thecan bodies. As the bodies are so carried along a horizontal plane, theyare passed within the confines of pairs of side guide rails 68 (theuppermost one on each side shown) and upper and lower guide rails 70,which can pass them to other suitable mechanisms such as turrets, beltsand other guide rails (not shown) to further remove the coated bodies toother stations for further processing such as baking and filling.

The right hand portion of FIG. 2 shows the uppermost of can bodies 44 intwo respective stacks thereof within guide rails 45, above theirrespective worm feed screws 40 (shown in FIG. 1) and 42 respectivelyhaving feed grooves 41 and 43 and being mounted on shafts 38 and 39 forsynchronously, simultaneously and timedly feeding can bodies 44 ontocradles 46 and valves 50 of rotating drum 12. Also shown are portions ofcables 72 broken away on their respective, also broken away, rollers 74and 76.

FIG. 3 is an enlarged section taken substantially along line 3-3 ofFIG. 1. More particularly, FIG. 3 shows drum 12 having front convex wall51, cylindrical wall 52 and rear concave wall 53. Valves 50 are mountedon cylindrical wall 52 by insulating mounts, generally designated 49,which also insulatedly mount cradles 46 (broken away) having at theirupper ends, notches 134 between and defined by spaced tines 133.

Fastened or attached to the rear of concave drum wall 53 as by weld 86are arms 88 of a spider structure 87 whose flanges 89 have screws 90passing therethrough and which fasten rear drum wall 53 to main ringgear 20 having peripheral teeth 21. As motor driven pinion gear 18(FIG. 1) drivingly rotates main ring gear 20 and drum 12, the ring gearrotates on friction free ball bearings 92 in grooves within the insideof main gear 20 and within the exterior side of track 94 fixedlyattached by screws 96 through its flange to bracket 99 in turn fixedlyattached to main frame 15.

Attached to the interior of rear drum wall 53 by means of bolts 280,rubber spacers 282 and fastening rings 284, is a portion of the meansfor creating a potential between electrodes 48 and interiorelectricallyconductive surface areas of can bodies 44 mounted on valve50. The aforementioned portion of the potential creating means can be acommutator assembly generally designated 96, having a housing 97comprised of a cylindrical wall 98 and front and rear walls 100 and 102.Housing 97 is mounted on hollow support 104 whose axis, it is to benoted, is concentric with that of main ring gear 20. Running throughhollow support 104 are means such as pipes 106 for draining, 108 forleveling, and 110 for filling drum 12 with an electrolytic fluid. Thepipes extend through hollow support enclosure cap downwardly into thelower portion of drum 12 to or into the upper level of fluid 84represented by dashed line 85 (pipe not being shown). The rear portionsof pipes 106, 108 and 110 can be connected to suitable means such aspumps for pressuredly or otherwise quickly effecting the draining,leveling and filling actions.

Also extending through hollow support 104 is conduit 112 for carryingwire 114 which can be connected exteriorly of drum 12 to a suitableportion of the'potential creating means such as a voltage source (notshown). Conduit l 12 carries wire 114 into commutator assembly 96 whereit is attached to other portions of the aforementioned means forcreating a potential.

As mentioned previously, commutator assembly 96 is affixed to drum 12and rotates therewith. Connected to commutator assembly exteriorcylindrical wall 98 and communicating with a portion of the means forcreating a potential within commutator assembly 96 are offsetfluid-proof terminals generally designated 116 on the upper, frontportion, and 116' on the lower rear portion of cylindrical wall 98. Alsoconnected to commutator assembly cylindrical wall 98 are bolts 119' inthe upper rear end, and 119 at the lower front end of wall 98.Theirfunction will be explained later. Connected to and running fromterminals 116 and 116 is intermediate circuitry comprising respectivewires 120 and 121, and 120 and 121' which are part of the potentialcreating means and which pass through the interior of drum 12, throughapertures in guide mounts and are respectively connected to valves 50 bysuitable electrical connecting means such as fluid-proof terminals 122on the front and rear portions of drum l2. Wires 120 and 121 and 120'and 121' communicate with and are connected to electrodes 48, as shownlater. Guide mounts 125 reduce the slack of the aforementioned wires andprevent them from flopping around in drum 12 as it rotates. Mounts 125also act as nuts for insulating mounts 49 on the exterior of cylindricalwall 52.

FIG. 3 also shows pinion gear 24 fixed to shaft 25 whose central axis,it is to be noted, is offset towards the reader from the axis of hollowsupport 104. Shaft 25 runs through bearing 128 attached through itsflange byscrews 130 to bracket 99, and it runs through pulley 26 towhich it is fixed and drivingly rotates. Pulley 26 drives belt 27 whichdrives pulley 28 fixedly mounted to shaft 29 running through supportbearing 130. Shaft 29 is fixedly connected to pulley 30 which drivesbelt 31 shown broken away but connected to other pulleys for driving thefeeding and discharge means (FIG. 1). Support bearing 130 is fastened bymeans of screws 132 through its flange to frame 15.

It is to be noted that the axis of hollow support 104 and shafts 25 and29 are not horizontal but are slightly tipped so that drum 12 is angledslightly outwardly from its top to its bottom. Drum 12 is slightlyangled in this manner so that no interior wall surface of the drumextends ina horizontal direction. This is to assure that electrolyticfluid on any interior wall surface of drum 12 can run in at least asomewhat downward direction toward the bottom of the drum for draining.This angularity helps to keep the interior surfaces of the drum clean bypreventing fluid material or particles from accumulating on interiorsurfaces of the drum.

The lower portion of drum 12 shows the bottom closed ends of can bodies44 pressuredly and sealingly engagedly mounted on valves 50, filled withelectrolytic fluid 84 (not shown) and held in such mounted position byholding means such as continuous cables 72 extending substantiallyaround the circumference of cylindrical drum wall 52. Cables 72 exertaxial pressure against the bottom ends of the can bodies. Cables 72 canbe prevented from falling off bodies 44 (or 44) and can be held in asubstantially diametrical position relative thereto by being held innotches 134 between and defined by spaced tines 133 adjacent the ends ofcradles 46.

The upper portion of FIG. 3 shows cables 72 no longer pressuredlyengaging the bottom ends of coated can bodies 44'. It shows separatingknives 135 having separated the rims of bodies 44 from valves 50 so thatrespective pairs of discharge belts 64 engaging each side of respectivebodies 44' can carry the bodies from the drum in a substantiallyhorizontal plane as drum 12 cooperatively continues to rotate and carryvalves 50 and electrons 48 in a circumferential arc downwardly out ofthe bodies 44'. Belts 64 carry the bodies to guide rails 68 and 70 (notshown).

FIG. 4 is an enlarged perspective view of one of cradles 46 shown brokenaway in FIG. 3. More particularly, FIG. 4 shows a cradle generallydesignated 46 having leg mount 131, arms 132 and spaced tines 133defining notch 134 into which cable 72 fits during a major portion ofthe rotation of drum 12. Leg mounts 131 are fastened by bolts ofinsulating mounts 49 to drum cylindrical wall 52. Arms 132 help receive,register and keep registered bodies 44 on valve means 50, duringrotation of drum 12. They also maintain bodies 44' in position whencables 72 lose contact with the bottoms of bodies 44' at approximatelythe 12 oclock position (FIG. 1).

FIG. 5 is an enlarged section taken substantially along lines 55 ofFIG. 1. More particularly, FIG. 5 shows valve means such as a fluidvalve, generally designated 50, mounted in a wall of a reservoir such ascylindrical wall 52 of reservoir or drum 12, the valve means being shownin its closed position with no fluid in its chamber and no containerbody on its sealing rim 156.

Fluid valve means 50 is comprised of a fixed exterior housing, generallydesignated 136, fixedly mounted on cylindrical drum wall 52 by means ofa substantially L- shaped sealing gasket 138, the exterior housinghaving a side wall abutting gasket 138 and having a rigid back wall 142proximate the interior of drum l2 and having apertures 144 therein (oneshown) communicating with a portion of the interior of drum 12 whichdoes not contain any of fluid 84. Fluid valve 50 is also comprised of amoveable interior housing 146 interior of and slidingly engagingexterior housing side wall 140 and defining a central chamber 148.Interior housing 146 has a mouth generally designated 150 and defined byflanges 152 and 154, in which is mounted and seated a resilient sealingring 156 which is biased by biasing means such as helical spring 158 incutout portion generally designated 160 in the exterior wall of interiorhousing 146. The biasing being sufficient to sealingly engage sealingring 156 against legs 162 of fixed valve member generally designated 164fixedly connected through current carrying means such as core 166 toback wall 142 adjacent apertures 144 in exterior housing 136. Connectedto and extending or projecting from valve member 164 is an electrodesuch as helical spring 48 connected to head 168 of phillips screw 170,also part of the current carrying means, threadedly engaged to core 166.Biasing means 158 includes rigid backing ring 172 located adjacent backwall 142, and one or more rigid lock washers 174 mounted between ring172 and spring 158, for backing and biasing the spring and interiorhousing 146 outwardly toward and against legs 162 of valve member 164.Both ring 172 and lock washer 174 are located betweeninner housing 146and exterior housing side wall 140.

Abuttingly engaged between the interiormost edge of backing ring 172 andan adjacent portion of exterior housing wall 140 is a fluid sealing andpreventing means which includes a flexible and resilient annularinterior sleeve 176 and an annular elastomeric O-ring 178 for sealingand preventing fluid from chamber 148 from passing between interior andexterior housings 146 and 136. Interior sleeve 176 extends betweenannular O-ring 178 and backing ring 172, around the interiormost edge180 of interior housing 146 and is abuttingly engaged and compressedlyfastened within an annular groove 182 in the interior wall of interiorhousing 146 defining chamber 148, by means of one or more rigid lockwashers 184 (not shown) which peripherally forces adjacent portion ofinterior sleeve 176 into annular groove 182.

Also included as part of the fluid sealing and preventing means is aresilient flexible annular exterior sleeve 186, having flange 188engagingly extending around interior housing flange 154 and abuttinglyengaging sealing ring 156. Exterior sleeve 186 has an interior annularbead 190 abuttingly engaging the comer of interior housing flanges 152and 154. Exterior sleeve 186 has at its interiormost end an integral,annular, exterior bead 192 defining an adjacent annular sleeve groove194 within which an annular coiled garter spring 196 sealingly holdsexterior sleeve 186 within annular exterior housing groove 198 formed byannular exterior housing bead 200 and flange wall 202., Exterior sleeve186 is sealingly fastened to interior housing flange 154 by means suchas annular steel wire 204 which sealingly holds a portion of theexterior sleeve within annular groove 206 in the exterior of interiorhousing flange 154.

The upper portion of FIG. shows conductive metal wire portion 126 of aninsulated wire such as designated 120 (or 120, 121 or 122') (FIG. 3),descending through terminal generally designated 122 and comprised of aconnecting screw plug 123 having a nonconductive fluid-proof plastic orother suitable tubeshield 208 thereover. Plug 123 is threadedly engagedwithin the head of connecting screw jack 124 having a threaded shaft 212threadedly engaged within bore 214 of exterior housing backwall 142 andwithin core 166 of valve member 164. Wire 120 runs through the center ofplug 123 and extends down to and contacts a portion of jack head 124'.Plug 123 can be fastened to connector screw jack 124 or valve means 50inany conventional manner that will provide a fluid-tight seal and willallow plug 123 to be screwed into jack 124 without unduly twisting theconductive metal wire portion 126.

FIG. 5 shows electrical circuitry that is part of the potential creatingmeans of this invention. The circuitry includes conductive wire portion126 of wire 120, terminal 122, solid metal core 166, phillips screw 170,head 168, and helical spring electrode 48. Solid metal core 166 has anon-conductive moisture-proof polyolefin shield 167 therearound. Valvemember legs 162 are covered with a similar material (not numbered).

It is to be noted that all portions of fluid valve means 50 which are ormight be exposed to electrolytic fluid 84, excluding electrode 48, aremade of, covered with or otherwise isolated from the current carryingmeans by, a suitable non-conductive material. For example, the housingscan be manufactured of a commercially available rigid, moisture-proof,non-conductive material that will not gall with each other, such as anacetal resin sold under the trade designation Delrin, a trademark ownedby I. E. Dupont de Nemours and Co. Inc., for the interior housing, and acommercially available polycarbonate thermoplastic for the exteriorhousing. Annular sealing ring 156, can be made of an elastomer such asisoprene, and O-ring 178 and interiorand exterior sleeves 176 and 186 ofa suitable nonconductive flexible resilient non-permeable, fluidsealingelastomer such as a neoprene. The only metal parts employed interior ofexterior housing 136, i.e., spring 158, backing ring 172, and lockwashers 174 and 184, are effectively non-conductively isolated fromelectrode 48 or from any fluid 84 in or flowing through chamber l48.-Thecurrent carrying portions of fluid valve means 50, e.g., solid metalcore 166 and phillips screw 170, preferably are made of steel and areeffectively non-conductively isolated from contact with electrolyticfluid 84 and will therefore not have a buildup of particles thereonwhich would require maintenance, clean-upand possible clogging andinefficient operation of the valve means.

FIG. 6 is an enlarged cross section taken substantially along line 66 ofFIG. 3. More particularly, a fluid valve means 50 similar to that inFIG. 5 is shown in an open position. With sufficient axial pressureexerted by cable 72 against the bottom of container 44, its rim R ispresssuredly sealingly engages sealing ring 156 and pushes interiorhousing 146 inwardly against the bias of spring 158, such that interiorhousing flange wall 152 abuts exterior housing lip 201 and theinteriormost edge of interior housing 146 flexes interior sleeve 176inwardly towards aperture 144 of back wall 142. As interior housing 146is so moved inwardly and as sealing ring 156 about valve mouth 150 isalso moved inwardly, its interior angular wall 157 is moved inwardlyaway from legs 162 of valve member 164 to break its sealing engagementtherewith and thereby create a passageway P between sealing ring 156 andlegs 162 which allows electrolytic fluid 84, which had been in thebottom of drum 12 and within valve chamber 148, to gravity-passdownwardly through passageway P and fill container body 44.

As will be explained in detail in relation to FIG. 8, during a portionof the rotation of drum 12 when electrolytic fluid 84 is withincontainer body 44, a potential difference is created between springelectrode 48and interior electrically-conductive surface areas of wallsW of container body 44. Due to the potential created, electric currentflows through the circuit comprising the electrode, the fluid and themetal conductive body surface areas. Coating particles are therebydeposited on the surface areas to fully coat their entirety or to repaircoat discontinuities in a base coat thereon.

FIG. 7 is a plan view taken substantially along line 77 of FIG. 6 andshows an upper portion of exterior housing back wall 142 having abevelled edge 143, and having apertures in the wall defined by arcuatewalls 144 and in part by wall 147 of exterior housing 136. FIG. 7 alsoshows a cross section through the threaded, shaft portion 212 ofconnector screw jack 124 threadedly fastened within bore 214 to backwall 142.

' FIG. 8 is a front elevation taken from the inside of drum 12 justinterior of front wall 51 in FIG. 3. FIG. 8 shows front wall 216 ofenclosure cap having ports 222 and bolts 218 in holes 220 for. securingenclosure cap 105 to wall 103 of hollow support 104.%Wall 103 has astepped surface 103 therein. Enclosure cap ports 222 join and housepipes 106, 108 and entering from hollow support 104, and their brokenaway portions descending therefrom towards the bottom of drum 12 (notshown).

FIG. 8 also shows front wall 100 of commutator assembly 96 having aprotruding stepped portion 101 whose lowermost surface 101 of itslowermost flange is just above cylindrical surface 224 of enclosure cap105.

The lower, broken away portion of commutator assembly 96 shows mountedwithin drum 12, a portion of the potential creating means of thisinvention. It is to be noted that commutator assembly 96 of FIG. 3should be considered as divided transversely in half, and that thelargest broken away portion of FIG. 8 shows a portion of the front halfof the commutator assembly (see FIG. 9). The dashed upper portion ofFIG. 8 is also the front portion of the assembly interior of housingwall 100.

The large broken away portion of FIG. 8 shows electrical cam bar 228fastened to crib 230 of cam support 232 by means of bolts 234 whosethreaded shafts pass through apertures 236 and are threadedly engaged tocam bar 228 in the rear portion (not shown) of commutator assembly 96.

It is also to be noted that cam support 232 on which is mounted cam bar228, a fixedly mounted upon fixed hollow support 104 which is in turnfixed to bracket 99. Commutator assembly housing 97 (FIG. 3) includingits exterior front wall 100, protruding stepped portion 101 cylindricalwall 98 and cylindrical wall rib 238, and all of the structure shownmounted on wall 98 and its rib 238 peripheral to or below cam bar 228,rotate around the aforementioned fixed structures 232, 228 and 104.

Cylindrical wall 98 has U-shaped cut-outs 240 in its rib 238 and isfastened to the periphery of housing wall 100 by means of nuts 242 beingthreadedly fastened to shafts 243. Wall surface 244 of cylindrical wall98 abutting the interior of wall 100 shows shaft 243 in section. Spacers248 are mounted on shafts 250. Pivot arms 246 are rotatably mounted onshafts 250 (front ends shown) which pass within bores 241 in rib 238 ofcylindrical wall 98. Pivot arms 246 have stop portions 252 which limittheir rotation by abutting interior wall surface 245 of cylindrical wall98. Pivot arms 246 also have electrical contacts which can be carbonbrushes or studs 254 mounted therein by their shafts 256 (FIG. passingthrough arm bores 258 (FIG. 10) and being threadedly engaged by nuts 259(FIG. 10). Secured to shafts 256 between nuts 259 and the bottomsurfaces of pivot arms 246 are electrical connecting lugs 260 havingwires 121 therein which extend over spacers 248, down through holes 262extending radially through cylindrical wall 98, through terminals 116and through the interior of drum 12 to terminals 122 of valves 50.Each-wire 121 is joined as by splicing to another wire 120 and each wire120 and 121 extends fairly tautly within drum 12 to cylindrical wall 52thereof, where they are electrically connected to valves 50, as shown inFIG. 3.

' FIG. 8 also shows a more deeply broken away portion of cylindricalwall 98 directly underlying contacts 254. FIG. 8 there shows asubstantially Y-shaped bore 264 in wall 98 having threadedly secured toits lower portion a threaded stud shaft 266 of a bolt 119, the end ofwhich provides a backing for biasing means, such as helical spring 268,which abuttingly engages contact shaft 256 and nut 259 on the lower endof contact 254 and thereby normally biases contact 254 in its uppermostposition. Contacts 254 remain in this position throughout most of therotation of cylindrical wall 98, commutator assembly 96, and drum l2,i.e., except for the period of rotation during which the contacts engagearcuately shaped surface 229 of cam bar 228. As contacts 254 are rotatedclockwise and are passed upwardly to the left around and againstelectrical cam bar 228, they are moved downwardly on pivot arms 246against the bias of springs 268.

Although FIG. 8 only shows a few of the contacts, rocker-arms, spacers,terminals, etc., it is to be understood that such mechanisms are locatedall the way around the periphery of cylindrical wall 98 of commutatorassembly 96.

As mentioned previously, it is to be noted that commutator assembly 96should be considered as having two halves and that the broken awayportions of FIG. 8 show only the front portion of the front half of thecommutator assembly. This can be more clearly seen in FIG. 9 which is anenlarged top view taken in section through lines 99 of FIG. 8. The lowerportion of FIG. 9 is the front of commutator assembly 96. If oneconsidered front commutator assembly wall removed from FIG. 9, the frontof FIG. 9 would then show the largest cut away portion of FIG. 8.

Shown in FIG. 9 are pivot arms 246 having contacts 254 whose shafts 256(not shown) are mounted in bores 258 therein and secured thereto by nuts259 (not shown) which also secure electrical connecting lugs 260 topivot arms 246. Pivot arms 246 are mounted on shafts 250 passing throughand mounted in cylindrical wall rib 238 by means of nuts 274 withinU-shaped grooves 240, being threadedly engaged to shafts 250. Shafts 250pass through bores 241 in rib 238 and have integral nut-shaped flanges278 acting as spacers be tween rib 238 and pivot arms 246. Shafts 250also have mounted thereon spacers 248 which cooperate with flangespacers 278 to maintain pivot arms 246 in an aligned position so thatthe rotary path of commutator assemblys cylindrical wall 98 will bringcontacts 254 into aligned contact with cam bar 228. FIG. 9 shows wire121, crimped to and running from connecting lug 260, passing over spacer248 down through hole 262 (dotted circles under spacers 248) incylindrical wall 98 and down through terminal 116 (not shown) whoseconnecting screw jack 118 (not shown) is mounted in the bottom ofcylindrical wall 98. Also shown in FIG. 9 are Y-shaped bores 264, undercontacts 254 (here removed), the bores having springs 268 mountedtherein and biased upwardly towards the reader by bolt stud shaft 266.

The rear portion of FIG. 9 is a duplication of the structure justdescribed for the front portion of FIG. 9, except that the rearstructures, it is to be noted, are given primed numerical designationsand they are offset from the structures in the front.

FIG. 10 is a cross section taken substantially along line l0l0 throughcommutator asssembly 96 of FIG. 8. More particularly, FIG. 10 shows,mounted within drum 12 on rear wall 53 by means of bolts 280, spacers282 and ring 284, commutator assembly 96 having rear wall 102 secured torear drum wall 53 and front wall 100, and, fixed therebetween,cylindrical wall 98. The upper portion of FIG. 10 shows rib 238 ofcylindrical wall 98 having shaft 250 extending therethrough and beingsecured to rib 238 by means of nut 274 in U- shaped groove 240. Shaft250 has integral flange spacer 278 betweeen pivot arm 246 and rib 238.Wire 121 is shown passing from within commutator assembly 96 throughbore 262, terminal connecting screw jack 118, and connecting screw plug117, where it is joined by wire 122, both wires passing to valves oncylindrical drum-wall 52 (not shown).

That portion of cylindrical wall 98 and commutator assembly 96 shown tothe right of rib 238, which in FIGS. 8 and 9 has been called the rear ofthe commutator assembly, shows contact 254' mounted on shaft 256' andsecured to rocker arm 246 by nut 259'. Contact 254' is biased in adownward direction by spring 268' and by threaded stud shaft 266' ofbolt 119.

The lower portion of FIG. 10 shows front cam bar 228 and rear cam bar228 secured to cam support ring 232 by means of bolt 234 passing withinapertures 236 (not shown) and being threadedly engaged to cam bar 228'.FIG. 10 shows contact 254 mounted on rocker arm 246 and being biasedagainst and contacting cam bar 228 to thereby close a circuit whichallows electrodepositing current to flow from a voltage source (notshown) through wire 114 in conduit 112, connecting lug 272, bolt 234,cam bar 228, contact 254, shaft 256, connecting lug 260, wire 12], whichpasses over spacer 248 and passes down through offset front structurenot shown, i.e., bore 262 and terminal 116 comprising connector screwjack I18 and connector screw plug 117 (such as shown in FIG. 8). At theexterior of terminal 116, as in FIG. 8, wire 121 is joined by wire 120and both wires run as part of intermediate circuitry to valves 50 on thelower portion of drum 12 (not shown). The aforementioned structure notshown in FIG. 10 but shown in FIG. 8, is the same as the structurethrough which wire 121" passes at the lower rear of FIG. 10.

Commutator assembly 96 and all of its housing walls 100, 98 and 102(affixed to rear drum wall) rotate with drum 12 around fixed hollowsupport 104 secured through its flanges to frame bracket 99 by bolts286. Commutator assembly 96 rotates around cam support ring 232 fixedlymounted on hollow support 104 by enclosure cap 105 being bolted by bolts218 to hollow support wall 103 whose recessed flange surface 226 abutsspacer 288 whose hub 290 abuttingly and fixedly engages cam support ring232 against wall stepped surface 103".

FIG. 10 also shows that the lower interior surfaces of protrudingstepped front wall 101 has flange rings (unnumbered) which cooperatewith grooves and opposing flange rings in spacer 288 to form a labyrinthseal for preventing fluid within drum 12 from passing through channel290 and splashing into commutator assembly 96. FIG. 10 also shows drainpipe 106 (broken away) passing through hollow support 104 and throughport 222 downwardly into drum l2. Conduit 112 passing through theinterior of hollow support 104 has an elbow 113 and is secured tosupport 104 by nut 292 engaging flanges of support 104.

As shown in FIG. 9, contacts 254 and 254' are staggered, each separatelysending current through wires 121 and 121, respectively staggeredterminals 116 and 116', and joining wires 120 and 120', each of whichwires 120 and 121 goes to one of an aligned pair of valves 50-and wires121 and 121 to the next aligned pair of valves 50 on cylindrical wall 52of drum 12. This staggered arrangement of contacts 254 and 254' meansthat as a front contact 254 engages cam bar 288, one will leave 288,during which time the number of rear contacts 254 does not change. Thiskeeps the current load fairly constant by not making more simultaneouscontacts and therefore larger current demands.

The electrocoating system of this invention for electrodepositing acoating on interior electricallyconductive surface areas of containerbodies, can be operated by a method which comprises starting the meansfor rotating the reservoir, i.e., the drive means which includes themotor 16, which in turn drives pinion gear 18 in a counterclockwisedirection. This drives main ring gear 20 and reservoir or drum 12attached thereto, in a clockwise direction. Main ring gear 20 in turndrives pinion gear 24 and the aforementioned series of belts and pulleyswhich in turn ultimately drive feeding means 22 for feeding can bodies44 onto rotating drum l2, and also drive take-off or discharge means 23for taking the coated can bodies 44 off of drum 12 and discharging themfrom the system for further pro cessing at other stations.

In the preferred embodiment shown in the drawings, a plurality ofuncoated can bodies 44 from a source are individually passed throughguide rails 45'defining two stacks, the lowermost can body 44 of eachstack being taken within respective grooves 41 and 43 of respective wormfeed screws 40 (FIG. 1) and 42 (FIG. 2), which, as they rotate,simultaneously, synchronously and timedly feed their respective canbodies onto each cradle 46 of a pair from a radially-aligned continuousseries of such pairs mountedly aligned in two rows around thecircumference of synchronously rotating drum 12. Uncoated can bodies 44are passed from worm feed grooves 41 onto cradles 46 when the cradlesare at an angle which allows the can bodies to slide down the cradlesand over electrodes 48 protruding from each valve 50 mounted in thedrum. Thus, worm feed screws 40 and 42 cooperate with cradles 46 to feeduncoated can bodies 44 in register onto valve means 50.

As drum l2 continues to rotate in a clockwise direction, the rims ofeach row of uncoated can bodies 44 restingly. registered on valves 50are diametrically, pressuredly engaged by continuous cables 72 driven bydrum 12 to rotate in a clockwise direction over rollers 74 and 76. Thetautness of cables 72 caused by the passage of cables 72 over therollers maintains the diametrical pressured engagement with the bottomsof the can bodies throughout rotation of drum 12 until the coated canbodies 44', are taken off drum 12. As shown in FIG. 3, cables 72 arealigned with and are positioned within cradle notches 1340f spaced tines133 so that the cables remain aligned in diametrical position inrelation to the can bodies throughout the rotation of the drum. Cables72 provide sufficient axial presssure on the bottoms of the can bodiesto sealingly engage their rims against sealing rings 156 in mouths ofvalves 50, and to depress or move interior valve housings 146 inwardlyagainst the bias of their springs 158 to create passageways P betweenvalve member legs 162 and sealing rings 156. Cables 72 are taut enoughto maintain this pressure and to maintain passageways P fromapproximately the 3 oclock to approximately the 12 oclock rotationalposition of drum 12 (FIG. 1).

When the uncoated bodies 44 are sealingly engaged against valves 50 anda passageway has been created leading from drum 12 to the interiors ofthe bodies, drum l2 continues to rotate. As can bodies 44 on open valves50 are rotated downwardly, electrolytic fluid 84 within drum 12gravity-passes through passageways P into the interiors of bodies 44.Fluid 84 gravity-remains therein during drum rotation from about the 4oclock to about the 8 oclock rotation position during which time theelectrodeposition process takes place when contacts 254 and 254' engagecam bars 288 and 288. Fluid 84 in now coated bodies 44' gravity-passestherefrom through passageway P and drains back into drum l2. Fluid 84continues to drain therefrom as the coated bodies 44 continue to berotated from about the aforementioned 8 oclock position to about the l Ior 12 oclock position, where coated bodies 44 are removed from the drum.

Before uncoated bodies 44 on open valves 50 adjacent the 3 oclockposition are rotated downwardly to a position where fluid 84 begins topass into the can bodies, a voltage is created in the potential creatingmeans, e.g., in a power supply (not shown) sufficient to pass requisitecurrent through wire 114 in conduit 112 of hollow support 104, theelectrical circuitry of commutator 96, wires 120, 120 and 121, 121', andthrough valve members 162 of valves 50 to spring electrodes 48.

In the preferred embodiments shown in the drawings, electrode 48 iscathodic, and, current created therein and transferred to electrolyticfluid or coating medium 84 causes coating ions or polyelectrolyticparticles therein and carrying a negative charge to migrate to anddischarge onto interior electrically conductive, here positively,charged surface areas of the anodic metal can bodies. Thiselectrodeposition or electrocoating process takes place during the timethat contacts 254 and 254' engage cam bars 288 and 288', generallybetween about the 6 and 9 oclock rotational positions of drum 12, asshown in the broken away portion of FIG. 8. The length of time ofelectrodeposition can be varied by varying the length of the cam bars.

Coated can bodies 44' are held onto drum 12 by cables 72 until about the12 oclock position where the cables angle off the path of rotation ofdrum 12, and, as they leave the can bodies, the bodies are graspedbetween pairs of take-off or discharge belts 64 in a manner that allowsthe can bodies to be lifted from cradles 46 and from electrodes 48without the electrodes contacting interior surfaces of the bodies orcradles 46 touching previous removed cans. Both front and rear take-offor discharge means 23 are driven by main ring gear and by various beltsand pulleys and they are simultaneously operated in timed, synchronousrelationship with the rotation of drum 12 and with feeding means 22.

The reservoir or drum 12 of this invention can be of any suitable sizeor shape and can be of any suitable material. Preferably, the reservoiris drum-like and has a cylindrical wall. When the drum is made ofstainless steel or another conductive material, it is advantageous tocoat the interior of the drum with a suitable material such as aconventional asphalt-epoxy coating (discussed later), that will preventcoating ions or electrolytic particles from depositing upon andaccumulating upon the interior walls of the drum.

Fluid valve means 50 can be mounted in drum 12 in any suitable number,order, or arrangement, although it has been found advantageous to mountthem in one or more and preferably a plurality of rows of radiallyaligned pairs. All parts of valve means 50 exposed to electrolytic fluid84 are non-conductive in relation to fluid 84. They are isolated fromelectric current so that all exposed parts and moveable parts arenotsubject to an accumulation or build-up of coating ions or electrolyticparticles thereon. For example, conductive parts such as spring 158 andbacking ring 172 are isolated from fluid 84 by interior housing 146, andstainless steel core 166 of valve 50 is insulated from fluid 84 bynon-conductive thermoplastic insulative coatings such as 167 on valvemember 164.

Electrodes 48 preferably are helical springs for preventing can jam upon sealing rings 156 of valves 50. However, the electrodes can be of anysuitable conductive material or design sufficient to deposit therequisite amount of coating ions or electrolytic particles on allinterior electrically conductive surfaces areas of can body walls W. Theelectrode can be of any size or shape sufficient to allow the registeredfeeding of uncoated can bodies 44 thereover and the systematiccontinuous take-off of can bodies 44 therefrom without the electrodestouching or otherwise preventing the take-off and discharge from theelectrocoating system.

Cradles 46 can be of any suitable shape and can be of any suitableconductive or'non-conductive materials. However it is advantageous thatthe cradle be conductive when the means for holding the uncoated canbodies 44 on valves 50 has and imparts a negative charge such as cables72 so that cradles 46 aid in passing this negative charge to the canbodies 44. When cradles 46 are conductive it is advantageous to mountthem on non-conductive mounts to insulate a conductive, e.g., steel drumtherefrom.

Feeding means generally designated 22 can include any suitable means forfeeding can bodies 44 in timed, simultaneous synchronous registeredfashion in relation to the rotation of drum 12 so that the bodies aredeposited in cradles 46 and are mounted on electrodes 48 and registeredon sealing rings 156 of valves 50. The feeding means includes cradles 46or other suitable means for registering the can bodies on the sealingring of valve means 50. Feeding means 22 also includes any suitablemeans such as continuous cables 72 for holding the bodies in registeredsealing engagement on sealing rings 156 and for providing pressuresufficient to create passageways P between valve member legs 162 andsealing rings 156.

This invention is suitable for use with can bodies having either one ortwo open ends. However, when the bodies have two open ends, the holdingmeans can include means for sealing the exteriormost open end of suchbodies to retain the electrolytic fluid 84 therein during theelectrocoating depositing process.

Take-off or discharge means 23 can include any suitable means such asknives 134 for separating the rims of the coated can bodies 44 from thevalve means 50, and can include any suitable means for removing thecoated can bodies 44' from radially protruding electrodes 48 and cradles46 without electrodes 48 contacting the can bodies or either structureinterferring with their removal. Discharge means 23 can also include anysuitable means such as guide rails or conveyors for transferring theremoved can bodies from the system to another location for furtherprocessing.

Container bodies suitable for having coating ions or electrolyticparticles deposited upon their interior electrically-conductive surfaceareas, can be any can body made of conventional materials such asaluminium, tinplate, tin-free steel (TFS), or black plate. The containerbodies coated according to this invention can be Z-piece bodies formaking 3-piece cans, or l-piece bodies for making 2-piece cans. Thecontainer bodies can have two open ends but preferably they only haveone open end. The two-piece bodies for coating can have any conventionalside seam construction, and the one-piece cans for coating can be drawnand ironed or impact-extruded.

As mentioned previously, can bodies 44, herebefore designated uncoatedhas been meant to include container bodies which do not have and areintended to receive a full single coat, or cans which have a base coatwhich requires a repair coat.

The means for creating a potential between electrodes 48 and can bodies44 can include any conventional power source. It has been foundadvantageous to employ a standard, conventional, low ripple-constantvoltage source such as that designated Model No.

SCR-500, manufactured by Electronic Measurements Inc.

The amount of voltage employed to electrodeposit a single or repair coatfrom an organic polyelectrolytic medium can be any sufficient amountdepending on the circumstances, preferably the least amount that willgive a satisfactory single or repair coat in the time desired for theparticular metal substrate and electrocoating medium employed. Typicalvoltages generally utilized in electrocoating processes are in the rangeof about 50-500 volts, more commonly from about 100-400 volts.

The polyelectrolytic electrocoating material mediums which can beemployed in the electrocoating system of this invention can be any ofthe organic resin containing materials utilizable as electrocoatingconcentrates or baths in metal electrocoating systems. The mediums canbe aqueous or non-aqueous, i.e., solvent containing, but preferably theyare aqueous. The mediums can be modified, extended, and stabilized withsolutilizers or other materials.

Examples of aqueous mediums which can be employed are those disclosed inU.S. Pat. No. 3,230,162 issued to A. E. Gilchrist on Jan. 18, 1966.Disclosed therein are numerous concentrate compositions generallycomprising about 50 to 95 percent by weight polycarboxylic acid resin,about 1 to percent water soluble amino compound and the balance water.The polycarboxylic acid resins are film-forming at electrodepositionbath temperatures, and are curable to a tack-free film.

acid.

Examples of non-aqueous polyelectrolytic electrocoating material mediumswhich can also be employed are disclosed in U.S. Pat. No. 3,463,714issued to W. D. Suomi and A. R. Ravve on Aug. 26, 1969. Disclosedtherein are electrocoating baths prepared generally by dissolving acarboxyl-containing polymer and a basic nitrogen-containing compound inan organic solvent and adding a sufficient amount of a polar organicnonsolvent having a solubility parameter greater than 12 and a hydrogenbond index greater than 7.5 to convert the solution into a suspension.

The polyelectrolytic electrocoating material mediums disclosed in theaforementioned patents are merely examples of some of the many aqueousand non-aqueous mediums which can be employed. For example, alsoutilizable are non-polycarboxylic acid resins such as rubber latticesuspended resins adsorbed by hydroxyl ions, and resins fonnulated forexample from phenolics, polyvinyl ethers, cellulosic resins, polyimidesand silicones.

That the electrocoating system of this invention can be employed toelectrocoat interior, electricallyconductive surface areas of can bodiesis shown in TABLE I wherein 2-piece drawn and 3-piece regular can bodies(respectively l-piece and 2-piece during the coating operation), fulland repair coated with aqueous electrocoating mediums or baths at ratesas fast as 2 seconds, approximately 600 cans/per minute, obtainedsatisfactory quick tests within the range of from 0 to l .0 ma.

TABLE I BATH EQUlV.

Solids Resisitivity TlME CANS QUICK TEST" EXAMPLES TYPE-CAN TYPE Contentohm/cm) T(F) VOLTAGE (seconds) MlN. (milliamperes) Full Coating IZ-piece A 10% 1.980 85 400 4 300 0-0.25

drawn aapprox. tinplate 2 do. do. do. do. do. 500 2 600 0.5-1.0

' approx. Repair Coating 3 3- iece B 2.5% adjusted to 200 3.5 380 0.57

FS 4,800 approx. Miraseam* do. do. 2.0% adjusted to 80 2.0 600 0-0.4

5.500 approx. 5 do. do. 2.1% adjusted to 80 100 .5 520 0-6.0

4,400 approx.

A and B Anodic aqueous electrocoating buths prepared by dilutin percentsolids solution. with ionized water. C5576 and X1222 are be ieved to berou acid-hydroxyethyl melhucrylute and containing no more than 20 wt. 1of total poly polymer units derived from hydroxycthyl methucrylute.

Other aqueous polyelectrolytic electrocoating material mediums which canbe employed according to this invention are disclosed in U.S. PatpNo.3,366,563 issued to Hart on Jan. 30, 1968. Generally, Hart discloses anaqueous electrocoating bath containing a so]- ubilized vehicle resinwhich comprises the reaction product of a drying oil fatty acid ester ora semi-drying oil fatty acid ester with an alpha, beta-ethylenicallyunsaturated dicarboxylic acid or an anhydride of such an C5576 (for A)and X l 222 (for B) (manufactured by Pittsburg Plate Glass Co.) to theindicated ghly 22 percent solids concentrate solutions of butylucrylate-styrenc-methacrylic mer units derived from methacrylic andcontaining no more than 7 wt. '1 oltotul The resistivity of the bathsused for full coating the tinplate bodies was unadjusted, whereas thatfor the 0 TFS bodies was adjusted by contacting the unadjusted 65 ployedin relation to the electrocoating system of this invention.

In the electrical coating circuitry of this invention, wire 114 (FIG. isconnected to the positive terminal of the power source (not shown), andis ultimately connected through the cam bars, contacts and valves toelectrodes 48, thereby rendering them cathodic. Wire 75 (FIG. 1) isconnected to the negative terminal of the power source and is ultimatelyconnected through the brushes and the cables to container bodies 44 and44, thereby rendering them anodic. When, as shown in TABLE I, an anodicelectrolytic fluid or bath such as X1222 fills the container bodies 44,and the contacts engage the cam bars, negatively charged electrolyticcoating particles in the bath migrate to, discharge onto and coat anypositively charged interior conductive surfaces of the anodic containerbodies.

It has been found highly desirable to isolate, and the embodiment ofthis invention essentially isolates, the interior surfaces of metal drum12 from the aforementioned coating circuit.

This prevents electrolytic particles in fluid 84 from beingelectrodeposited on any such surfaces exposed to the fluid, and itprevents power loss from the power source through the exposures, to drum12 which preferably is grounded.

Although electrolytic particles from electrocoating fluids would tend toincreasingly insulate the exposed area as it coated the area, somerecently developed fluids would not so readily coat the area andtherefore would allow power loss.

The coating used to insulate the interior of drum 12 can be any coatingor coatings suitable for insulating the drum. The type of coating willvary depending on the type of material used to make the drum. For thestainless steel drum of this invention, it has been found advantageousto condition the interior surface as by sand blasting, and to treat thesurface with a 0.3 to 1 mil thick layer of a material such as analcoholic solution, e.g., a Polyclutch Wash-Primer preparable by thoseskilled in the art according to MIL Specification MIL-045328, designatedUC-40082, by PPG Industries, Inc. A conventional, commercially availablematerial such as a two component system, polyamidecured, heavy duty coaltar epoxy sold under the trade designation UC40101 by PPG Industries,Inc. can be applied over the primed surface in thick layers of say about6 mils each.

Of course, when drum 12 is not made of a conductive metal but is made ofsay a molded, cured glass filament epoxy material, the aforementionedcoatings would not be employed.

I claim:

1. A fluid valve for electrodepositing systems wherein an electrolyticfluid and electric current insulatedly pass through the valve, whichcomprises:

a fixed exterior housing mountable on a wall of a reservoir containingthe fluid, the exterior housing having a back wall with aperturestherein communicating with the interior of the reservoir,

a moveable interior housing, interior of and slidingly engaged with theexterior housing, the interior wall of the interior housing defining acentral valve chamber having a mouth opposite the back wall,

a resilient sealing ring mounted in the mouth,

a valve member fixedly connected at one of its ends to the back wall,extending axially into the chamber and having legs fixed to andextending transverse to its axis, the axial portion of the valve memberhaving a conductive core connectable to circuitry,

an electrode connected to and projecting from the exterior of the valvemember,

means for sealing and preventing fluid from passing between thehousings, and

biasing means between the housings for flexibly biasing the sealing ringof the interior housing in sealing engagement with the valve member legsto seal the fluid valve chamber, the biasing means being inwardlycompressible toward the back wall by an axial force, so that when theforce is sufficient to compress the sealing ring and biasing means, apassageway is created between the valve member legs and the sealing ringwhich allows fluid to flow from the reservoir to the exterior of thevalve chamber.

2. The fluid valve of claim 1 wherein all parts of the valve meansexcluding the electrode, exposable to the fluid, are non-conductive inrelation to the fluid.

3. The fluid valve of claim 2 wherein the biasing means is a helicalspring extending around and being abuttingly biased against a supportwall of, the interior housing.

4. The fluid valve of claim 3 wherein the biasing means also includes arigid backing ring adjacent the back wall of the exterior housing forbacking the spring. 7

5. The fluid valve of claim 4 wherein the fluid sealing and preventingmeans includes an annular flexible resil ient interior sleeve partlywithin the chamber and sealingly fastened to the interior of theinterior housing and the exterior of the exterior housing to preventfluid from passing therebetween.

6. The fluid valve of claim 5 wherein the interior housing has acontinuous annular groove therein and the interior sleeve is sealinglyengaged to the interior housing by means of at least one lock washerwhich peripherally forces an adjacent portion of the sleeve into theinterior housing groove.

7. The fluid valve of claim 6 wherein the fluid sealing and preventingmeans includes an annular flexible resilient exterior sleeve sealinglyfastened to and for sealing the exteriors of the interior and exteriorhousings, exterior of the reservoir wall.

8. The fluid valve of claim 7 wherein the electrode is a helical spring,the biasing means also includes a rigid lock washer mounted between thebacking ring and the spring for backing the spring and acting as a stopagainst outward movement of the interior housing, and the fluid sealingand preventing means also includes an annular elastomeric O-ring betweenthe back wall and an interior sleeve portion that is adjacent thebacking ring.

1. A FLUID VALVE FOR ELECTRODEPOSITING SYSTEMS WHEREIN AN ELCTROLYTICFLUID AND ELECTRIC CURRENT INSULATEDLY PASS THROUGH THE VALVE, WHICHCOMPRISES: A FIXED EXTERIOR HOUSING MOUNTABLE ON A WALL OF A RESERVOIRCONTAINING THE FLUID, THE EXTERIORR HOUSING HAVING A BACK WALL WITHAPERTURES THEREIN COMMUNICATING WITH THE INTERIOR TO THE RESERVOIR, AMOVEABLE INTERIOR HOUSING, INTERIOR OF AND SLIDINGLY ENGAGED WITH THEEXTERIOR HOUSING, THE INTERIOR WALL OF THE INTERIOR HOUSING DEFINING ACENTRAL VALVE CHAMBER HAVING A MOUTH OPPOSITE THE BACK WALL, A RESILIENTSEALING RING MOUNTED IN THE MOUTH, A VALVE MEMBER FIXEDLY CONNECTED ATONE OF ITS END TO THE BACK WALL, EXTENDING AXIALLY INTO THE CHAMBER ANDHAVING LEGS FIXED TO AND EXTENDING TRANSVERSE TO ITS AXIS, THE AXIALPORTION OF THE VALVE MEMBER HAVING A CONDUCTIVE CORE CONNECTABLE TOCIRCUITRY.
 2. The fluid valve of claim 1 wherein all parts of the valvemeans excluding the electrode, exposable to the fluid, arenon-conductive in relation to the fluid.
 3. The fluid valve of claim 2wherein the biasing means is a helical spring extending around and beingabuttingly biased against a support wall of, the interior housing. 4.The fluid valve of claim 3 wherein the biasing means also includes arigid backing ring adjacent the back wall of the exterior housing forbacking the spring.
 5. The fluid valve of claim 4 wherein the fluidsealing and preventing means includes an annular flexible resilientinterior sleeve partly within the chamber and sealingly fastened to theinterior of the interior housing and the exterior of the exteriorhousing to prevent fluid from passing therebetween.
 6. The fluid valveof claim 5 wherein the interior housing has a continuous annular groovetherein anD the interior sleeve is sealingly engaged to the interiorhousing by means of at least one lock washer which peripherally forcesan adjacent portion of the sleeve into the interior housing groove. 7.The fluid valve of claim 6 wherein the fluid sealing and preventingmeans includes an annular flexible resilient exterior sleeve sealinglyfastened to and for sealing the exteriors of the interior and exteriorhousings, exterior of the reservoir wall.
 8. The fluid valve of claim 7wherein the electrode is a helical spring, the biasing means alsoincludes a rigid lock washer mounted between the backing ring and thespring for backing the spring and acting as a stop against outwardmovement of the interior housing, and the fluid sealing and preventingmeans also includes an annular elastomeric O-ring between the back walland an interior sleeve portion that is adjacent the backing ring.